build(deps): Bump proc-macro2 from 1.0.84 to 1.0.85 (#553)

Bumps [proc-macro2](https://github.com/dtolnay/proc-macro2) from 1.0.84
to 1.0.85.
<details>
<summary>Release notes</summary>
<p><em>Sourced from <a
href="https://github.com/dtolnay/proc-macro2/releases">proc-macro2's
releases</a>.</em></p>
<blockquote>
<h2>1.0.85</h2>
<ul>
<li>Mark some tests as only for 64-bit targets (<a
href="https://redirect.github.com/dtolnay/proc-macro2/issues/463">#463</a>)</li>
</ul>
</blockquote>
</details>
<details>
<summary>Commits</summary>
<ul>
<li><a
href="https://github.com/dtolnay/proc-macro2/commit/5ee1cabadb40abe12abe27e3b34de8fc6f60bc0a"><code>5ee1cab</code></a>
Release 1.0.85</li>
<li><a
href="https://github.com/dtolnay/proc-macro2/commit/aa64c2007390a33d4edbc07aa3e576848ae3d653"><code>aa64c20</code></a>
Merge pull request <a
href="https://redirect.github.com/dtolnay/proc-macro2/issues/464">#464</a>
from dtolnay/testsize</li>
<li><a
href="https://github.com/dtolnay/proc-macro2/commit/bc9f4d938058be43d38f921f34f48b94a25278b7"><code>bc9f4d9</code></a>
Ignore size tests on non-64bit target</li>
<li><a
href="https://github.com/dtolnay/proc-macro2/commit/1160ec3c7d723e115c5acf2b4e9f00c2c049e84a"><code>1160ec3</code></a>
Make size tests #[ignore] in cfg(randomize_layout)</li>
<li>See full diff in <a
href="https://github.com/dtolnay/proc-macro2/compare/1.0.84...1.0.85">compare
view</a></li>
</ul>
</details>
<br />


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